<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">


<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    
    <title>Cell Objects &mdash; Python 3.4.3 documentation</title>
    
    <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
    <link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
    
    <script type="text/javascript">
      var DOCUMENTATION_OPTIONS = {
        URL_ROOT:    '../',
        VERSION:     '3.4.3',
        COLLAPSE_INDEX: false,
        FILE_SUFFIX: '.html',
        HAS_SOURCE:  true
      };
    </script>
    <script type="text/javascript" src="../_static/jquery.js"></script>
    <script type="text/javascript" src="../_static/underscore.js"></script>
    <script type="text/javascript" src="../_static/doctools.js"></script>
    <script type="text/javascript" src="../_static/sidebar.js"></script>
    <link rel="search" type="application/opensearchdescription+xml"
          title="Search within Python 3.4.3 documentation"
          href="../_static/opensearch.xml"/>
    <link rel="author" title="About these documents" href="../about.html" />
    <link rel="copyright" title="Copyright" href="../copyright.html" />
    <link rel="top" title="Python 3.4.3 documentation" href="../index.html" />
    <link rel="up" title="Concrete Objects Layer" href="concrete.html" />
    <link rel="next" title="Code Objects" href="code.html" />
    <link rel="prev" title="Instance Method Objects" href="method.html" />
    <link rel="shortcut icon" type="image/png" href="../_static/py.png" />
    <script type="text/javascript" src="../_static/copybutton.js"></script>
    <script type="text/javascript" src="../_static/version_switch.js"></script>
    
 

  </head>
  <body>  
    <div class="related">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             accesskey="I">index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="code.html" title="Code Objects"
             accesskey="N">next</a> |</li>
        <li class="right" >
          <a href="method.html" title="Instance Method Objects"
             accesskey="P">previous</a> |</li>
        <li><img src="../_static/py.png" alt=""
                 style="vertical-align: middle; margin-top: -1px"/></li>
        <li><a href="https://www.python.org/">Python</a> &raquo;</li>
        <li>
          <span class="version_switcher_placeholder">3.4.3</span>
          <a href="../index.html">Documentation</a> &raquo;
        </li>

          <li><a href="index.html" >Python/C API Reference Manual</a> &raquo;</li>
          <li><a href="concrete.html" accesskey="U">Concrete Objects Layer</a> &raquo;</li> 
      </ul>
    </div>    

    <div class="document">
      <div class="documentwrapper">
        <div class="bodywrapper">
          <div class="body">
            
  <div class="section" id="cell-objects">
<span id="id1"></span><h1>Cell Objects<a class="headerlink" href="#cell-objects" title="Permalink to this headline">¶</a></h1>
<p>&#8220;Cell&#8221; objects are used to implement variables referenced by multiple scopes.
For each such variable, a cell object is created to store the value; the local
variables of each stack frame that references the value contains a reference to
the cells from outer scopes which also use that variable.  When the value is
accessed, the value contained in the cell is used instead of the cell object
itself.  This de-referencing of the cell object requires support from the
generated byte-code; these are not automatically de-referenced when accessed.
Cell objects are not likely to be useful elsewhere.</p>
<dl class="type">
<dt id="c.PyCellObject">
<tt class="descname">PyCellObject</tt><a class="headerlink" href="#c.PyCellObject" title="Permalink to this definition">¶</a></dt>
<dd><p>The C structure used for cell objects.</p>
</dd></dl>

<dl class="var">
<dt id="c.PyCell_Type">
<a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a> <tt class="descname">PyCell_Type</tt><a class="headerlink" href="#c.PyCell_Type" title="Permalink to this definition">¶</a></dt>
<dd><p>The type object corresponding to cell objects.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyCell_Check">
int <tt class="descname">PyCell_Check</tt><big>(</big>ob<big>)</big><a class="headerlink" href="#c.PyCell_Check" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if <em>ob</em> is a cell object; <em>ob</em> must not be <em>NULL</em>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyCell_New">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyCell_New</tt><big>(</big><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*ob</em><big>)</big><a class="headerlink" href="#c.PyCell_New" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Create and return a new cell object containing the value <em>ob</em>. The parameter may
be <em>NULL</em>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyCell_Get">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyCell_Get</tt><big>(</big><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*cell</em><big>)</big><a class="headerlink" href="#c.PyCell_Get" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Return the contents of the cell <em>cell</em>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyCell_GET">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyCell_GET</tt><big>(</big><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*cell</em><big>)</big><a class="headerlink" href="#c.PyCell_GET" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the contents of the cell <em>cell</em>, but without checking that <em>cell</em> is
non-<em>NULL</em> and a cell object.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyCell_Set">
int <tt class="descname">PyCell_Set</tt><big>(</big><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*cell</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*value</em><big>)</big><a class="headerlink" href="#c.PyCell_Set" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the contents of the cell object <em>cell</em> to <em>value</em>.  This releases the
reference to any current content of the cell. <em>value</em> may be <em>NULL</em>.  <em>cell</em>
must be non-<em>NULL</em>; if it is not a cell object, <tt class="docutils literal"><span class="pre">-1</span></tt> will be returned.  On
success, <tt class="docutils literal"><span class="pre">0</span></tt> will be returned.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyCell_SET">
void <tt class="descname">PyCell_SET</tt><big>(</big><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*cell</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*value</em><big>)</big><a class="headerlink" href="#c.PyCell_SET" title="Permalink to this definition">¶</a></dt>
<dd><p>Sets the value of the cell object <em>cell</em> to <em>value</em>.  No reference counts are
adjusted, and no checks are made for safety; <em>cell</em> must be non-<em>NULL</em> and must
be a cell object.</p>
</dd></dl>

</div>


          </div>
        </div>
      </div>
      <div class="sphinxsidebar">
        <div class="sphinxsidebarwrapper">
  <h4>Previous topic</h4>
  <p class="topless"><a href="method.html"
                        title="previous chapter">Instance Method Objects</a></p>
  <h4>Next topic</h4>
  <p class="topless"><a href="code.html"
                        title="next chapter">Code Objects</a></p>
<h3>This Page</h3>
<ul class="this-page-menu">
  <li><a href="../bugs.html">Report a Bug</a></li>
  <li><a href="../_sources/c-api/cell.txt"
         rel="nofollow">Show Source</a></li>
</ul>

<div id="searchbox" style="display: none">
  <h3>Quick search</h3>
    <form class="search" action="../search.html" method="get">
      <input type="text" name="q" />
      <input type="submit" value="Go" />
      <input type="hidden" name="check_keywords" value="yes" />
      <input type="hidden" name="area" value="default" />
    </form>
    <p class="searchtip" style="font-size: 90%">
    Enter search terms or a module, class or function name.
    </p>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
        </div>
      </div>
      <div class="clearer"></div>
    </div>  
    <div class="related">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             >index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="code.html" title="Code Objects"
             >next</a> |</li>
        <li class="right" >
          <a href="method.html" title="Instance Method Objects"
             >previous</a> |</li>
        <li><img src="../_static/py.png" alt=""
                 style="vertical-align: middle; margin-top: -1px"/></li>
        <li><a href="https://www.python.org/">Python</a> &raquo;</li>
        <li>
          <span class="version_switcher_placeholder">3.4.3</span>
          <a href="../index.html">Documentation</a> &raquo;
        </li>

          <li><a href="index.html" >Python/C API Reference Manual</a> &raquo;</li>
          <li><a href="concrete.html" >Concrete Objects Layer</a> &raquo;</li> 
      </ul>
    </div>  
    <div class="footer">
    &copy; <a href="../copyright.html">Copyright</a> 1990-2015, Python Software Foundation.
    <br />
    The Python Software Foundation is a non-profit corporation.
    <a href="https://www.python.org/psf/donations/">Please donate.</a>
    <br />
    Last updated on Feb 26, 2015.
    <a href="../bugs.html">Found a bug</a>?
    <br />
    Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.2.3.
    </div>

  </body>
</html>